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About Gorgonops

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  1. You know, just for the heck of it I was doing some research, and I think the distinct possibility exists that I'm wrong about the need to use all 32 bits of a standard 72 pin SIMM in parallel. I ran across a few things you might be interested in. First off: an adapter to use a 16MB 72 SIMM in an old sound card that has 8-bit wide memory banks: https://www.vogons.org/viewtopic.php?f=46&t=41220&p=393886#p393886 And here, via Google Translate, another project to use a 72 pin SIMM to max out a Soundblaster AWE32, which has 16 bit wide RAM and uses two 30 pin SIMMs. This got me headscratching about how they pulled this off without wasting some of the RAM... and I *think* I get it now. Here's a link to a volume of old Micron datasheets; it includes sheets for both individual RAM ICs and assembled SIMM/DIMM modules. Long story short, if I'm interpreting the "theory of operations" correctly 72 pin modules have four separate CAS lines on them (which you would probably normally have tied together on the computer's side), and for a write to take you have to strobe the CAS line at the right part of the cycle. So, if I'm getting that correctly, it *is* possible to use a 72 pin SIMM as if it were four 8-bit banks of RAM, each 1/4 the capacity of the whole module. (Or split it into 2 16 bit banks, etc.) If that's actually the case I suppose I stand corrected on an earlier thread stating that the inability to do so is why you don't see Apple IIgs RAM cards made out of a single 72 pin SIMMs. The only thing I'm wondering is if it's really as easy as splitting the CAS signals from the original 30 pin banks up across the CAS lines on the SIMM or there's more to it than that. The pictures of the adapter for the GuS sound card make it look that easy, while the adapter for the Soundblaster suggests some massaging of the signals is necessary. Someone smarter than me needs to look at that Russian page. For this to work you'll have to have some external circuitry that tracks the RAS/CAS lines and does an "even/odd" thing to select one SIMM or the other for each half the address space. It should be relatively trivial but I'm not the one to ask. (It might also have implications for RAM refresh.) Presumably a single-bank 64MB would "naturally" look like 4 16MB 30 pin SIMMs without that.
  2. 30" Apple Cinema Display

    It does seem to be a problem with these monitors: https://discussions.apple.com/thread/1923154?start=0&tstart=0 But I haven't seen any solutions. I had a 23" die myself, and I vaguely recall "weirdness" with the USB hub before it pooped out entirely.
  3. There were FPM and EDO DIMMs; that's what was used in the "Beige Era" PCI PowerMacs. (Other than the Beige G3.) I honestly have no idea if anyone ever sold an adapter to put a pair of 72 pin SIMMs in a DIMM socket. Here's an important thing to think about: a "classic" 30 pin-to-72-pin SIMMsaver is taking 4 8-bit devices and paralleling them up to make them appear as a 32 bit wide device. And that's fine. If you're trying to do the reverse and take a wider memory and stick it in a narrower socket that's not fine. A 72 pin SIMM has a single read/write line that tells the bank of chips on the board to accept or produce a 32 bit word, all at once. Maybe this isn't going to be that much of a problem if you're looking to adapt a single 72 pin SIMM to feed a bank of 4 SIMM sockets because even though technically those sockets are going to contain within them 4 separate read/write signals it's *probably* safe to assume that if you just watch one of them you'll be okay. (IE, I don't *think* the memory controller in most computers would ever do "non-parallel" accesses to only a segment of the memory bank; even if the CPU is doing an unaligned 8-bit write the RAM controller takes care of doing the read-replace-write necessary to drop the changed byte into a 32 bit word. Although I wouldn't *swear* to it; if that's not true than your 30 pin wedge-o-tron will fail.) But if you're trying to use a 64 bit wide DIMM to replace *two* banks of 30 pin simms then you're in trouble. All 64 bits on that DIMM are in parallel, and always in parallel, you can't break it into two 32-bit (or eight 8-bit) chunks and assign a chunk to each memory bank. Which means without a write-before-read circuit to take care of the issues caused by trying to use one address on the DIMM for two addresses' worth of memory words (banks) you're definitively boned.
  4. MicroSD2ROMSIMM - SRAM based ROM emulator card?

    There's a dingus called the PETvet for Commodore PET computers (I was involved with brainstorming the idea for it over on the VCF, but, as usual for me, had no part in actually buckling down to build it) that essentially does what you're asking about here; it uses a small ATMEGA microcontroller to load a segment of an SRAM chip (which in this case is used to replace both the ROM *and* the RAM) with a copy of the Commodore ROMs (in this case stored in the ATMEGA's internal flash) and sets up the small SRAM that's used as a crude MMU to write protect it while holding the RESET line on the CPU. Once it's finished it allows the machine to boot. That's the major issue I see with this idea, really. Unless you have a battery in the system to make the SRAM non-volatile you'll have to load the "ROM" contents at power-on, and unless there's a way to hold the CPU in a halted state from the ROM socket while you're doing that you'll have the problem that the main CPU is going to try to start executing your uninitialized nothingburger when you flip the switch and crash horribly. Maybe a better idea would be to use flash chips (IE, basically the same as the existing ROM SIMM replacements) but simply build the programmer into the SIMM itself so you could tweak it at will just by leaving a USB cable hanging out the back. (You could always plug that into your Raspberry Pi if you wanted to program it over WiFi.)
  5. Apple, so far as I'm aware, only made a single RAM card, the 1MB capacity model that holds up to 32 41256 DRAMs in four banks of 8. Off the top of my head I'm pretty sure the first bank of RAM was soldered in those, so even an otherwise unexpanded IIgs should have 512k of RAM if *any* memory card is present. One thing I will say, I guess: out of two Apple IIgs' I started with one had the bad keyboard controller, while the other had bad RAM on the memory card, so I had to make one working one out of two. (I also later ended up taking the power supply out of dead keyboard to put in the working one because the caps in that one were really starting to smell like dead fish.) I suppose it's possible you've got some bad RAM going too. If you have the ability to generate disks for your GS you could try something like "Mousepaint". It's an 8-bit MacPaint wannabe that will run on a 128k IIe/IIc, so it should work on a IIgs with *no* cards present whatsoever, but I'm sort of thinking we're barking up the wrong tree here.
  6. CPU cache? I kind of doubt 256k of L2 cache is going to make that much difference in I/O bound processes. The faster SCSI ports on said card might certainly help overall but again, unless Apple was using *really* lousy hard drives in the Quadra 950 doing 1MB/second shouldn't be out of reach of the built-in SCSI chip.
  7. 44 seconds for a 30MB file is still pretty miserable. Regular old 10base-T should be able to beat that. (Should handle a bit over 1MB/s on a switched network; collisions will cut that down if you're using hubs, of course.) I suspect the real villain in this story is the overall crummy design of the classic MacOS. As evidence I present this snipped from the AWS95 Server Tuning Guide: Same hardware can blast almost four times the data through the Ethernet port under Unix than it can under regular System 7.
  8. It's definitely worth trying the machine in a stripped config and see if anything changes.
  9. Yeah, that sucks. The ROM1s had a number of teething problems between the keyboard controller issues and issues with early revs of the "Mega II" chip. The fact the keyboard works makes it seem likely it's one of those components, and the only sources for them are another IIgs motherboard. (The IIgs isn't really known for easy fixes like bad capacitors, at least on the motherboard. Power supply is another story.) Of course, there could be something I'm not thinking of so if anyone else has an idea by all means chime in.
  10. That's really strange. An ADB mouse should be plug-and-play on a IIgs. Is your IIgs a ROM1 or ROM3? Some revisions of the ROM1 motherboard are prone to maddening failures of the keyboard controller IC. (The same chip controls the ADB bus and the IIe-backwards-compatible matrix connector on the ROM1 board.) One of my IIgs' has a dead one, the symptom *it* expresses being doubled keypresses. (Doesn't matter if it's an ADB board or a IIe keyboard connected to the header, the errors are on the Apple II chipset side.) Hopefully it's something less dire than that, but it wouldn't surprise me if a problem with that could put the mouse to sleep.
  11. Strange Card, guessing this is the place for it?

    I was thinking the spacing looked awfully tight myself, but there are enough pins there. I'd love to see the other side. I wonder if they used some kind of crazy double-socket? I have really vague memories of once seeing such a thing. (As I recall it had a single plastic guide for two SIMMs; it held the two at different angles, one almost flat and the other at a taller angle.)
  12. a nice clamshell

    Be careful with those yo-yos, because they made them with two different size plugs. The Titanium G4 initially shipped with a Yo-Yo but its adapter has the same smaller-diameter plug as the later square adapters that were also used on the Snow iBooks. (I have an adapter like that buried in the garage somewhere. It gets scary hot if you plug it into a later, faster PowerBook G4, which isn't surprising because it was technically underspec'ed even for the 400/500s it shipped with.) So... wait, what was my point?... oh, yeah, make sure you get one with the right size plug, just being a Yo-Yo isn't enough.
  13. Geeze, yeah. That site seems to have been designed by someone who came to the odd conclusion that regular wikipedia's profusion of random links wasn't attention-deficit-inducing enough, they needed a version that turned all the related items into clickbaity pictures.
  14. Strange Card, guessing this is the place for it?

    Why do you think it was limited to a pair of SIMMs? It looks to me like there are two rows of pins for a total of four SIMM sockets on the other side of the board, and the text specifically talks about how the product needed to be able to accommodate whatever SIMMs a customer might already have on hand, since asking them to throw out their previous investment in an expensive 4MB upgrade would definitely have sunk whatever chances they might have had to sell it. The text talks about how the security function was (initially) sort of an afterthought. The main point of this product was to supply power and refresh signals to your RAM when the power was off to allow persistent RAM disks/slash/"instant on" desktops. The PDS connection was undoubtedly to supply circuitry/firmware that would override the normal power-on startup procedure. It's certainly an interesting widget; I'm particularly curious what it used the 16k of static SRAM onboard for. (Maybe when the board was set up it soft-loaded its "firmware" into it instead of using a ROM? Maybe it stored the security keys?)
  15. Strange Card, guessing this is the place for it?

    That's actually a picture of the Mac version of the product. Applefritter thread with pictures here: http://www.applefritter.com/content/macsaver-mac-memory-saver-and-guardcard